Ian Green, chief executive of the Terrence Higgins Trust, said: "The priority must now be to make sure that the trial reaches everyone at risk of HIV, and that it is rolled out speedily across the whole country, by the end of this year at the very latest - spring 2018 is not soon enough.

"To make sure no-one at risk of HIV is left behind, it is crucial that at the end of this trial, a clear process for routinely commissioning Prep on the NHS is agreed."

Deborah Gold, the chief executive at the National Aids Trust, said: "This is a pivotal moment in the fight against HIV.

"Prep, if targeted properly at those in need and at high risk of HIV, offers the possibility of transforming the English HIV epidemic.